Hydraulic system for controlling bulldozer blade

ABSTRACT

A single lever control valve means for controlling hydraulic actuators to pitch and tilt a bulldozer blade.

United States Patent Berg [54] HYDRAULIC SYSTEM FOR CONTROLLING BULLDOZER BLADE [72] Inventor: David A. Berg, Milwaukee, Wis.

[73] Assignee: Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

[22] Filed: Sept. 21, 1970 [2 1] Appl. No.: 73,836

[52] US. Cl ..l72/804, 91/413 [51] Int. Cl. ..E02t 3/76 [58] Field of Search ..l72/80l-807;

91/413; 74/471; 37/DIG. 7

[56] References Cited UNITED STATES PATENTS 3,184,869 5/1965 Olsen 17 2 s03 Oct. 24, 1972 3,540,220 "11/1970 Lauck ..91/413 x 2,224,725 12/1940 Felt, Jr. 172/804 5,122,850 3/1964 Rockwell ..172/s03 Primary Examiner--Robert E. Pulfrey Assistant Examiner-Stephen C. Pellegrino Attorney-Arthur L. Nelson, Kenneth C. McKivett and Robert B. Benson 5 7 ABSTRACT A single lever control valve means for controlling hydraulic aetuators to pitch and tilt a bulldozer blade.

10 Claims, 6 Drawing Figures HYDRAULIC SYSTEM FOR CONTROLLING BULLDOZER BLADE This invention relates to a hydraulic system controlling the bulldozer blade and more particularly to a single lever control valve means to operate hydraulic actuators for pitching and tilting a bulldozer blade.

A bulldozer blade on a tractor is generally mounted for universal movement relative to the chassis of the vehicle. A conventional C-frame pivotally mounted on the chassis carries a central universally connected pivotal arrangement supporting the central portion of the bulldozer blade. A ram provides assembly and support arms on each side of the C-frame supporting means for the bulldozer blade on each end and also universal connection to permit tilting, pitching, angling of the bulldomr blade relative to the vehicle chassis. A hydraulic actuator means is usually positioned for raising and lowering of the C-frame and bulldozer blade.

Angling of the bulldozer blade is not always hydraulically controlled and may be accomplished by a mechanical connection which can be preset prior to performing an earthmoving or excavating operation. Hydraulic control with hydraulic means on the ram assembly is, however used to extend or retract the ram assemblies and angle the bulldozer blade. Since this operation is used less often than the pitch and tilt operation it can be accomplished with a separate additional lever with no real inconvenience to the operator.

The pitch and tilt operations are used more frequently and for convenience a single lever control for both operations provides a more versatile arrangement for movement of the bulldozer blade. The pitch and tilt operations are actuated by separate hydraulic actuators connected between the C-frame and the bulldozer blade. The separate actuators are operated by separate valves through a lever arrangement.

Accordingly, this invention provides a simplified control utilizing a single lever which pivots on two axes. A hydraulic actuator is positioned in each ram assembly which pivots the upper portion of each side of the blade forwardly or rearwardly relative to the lower portion of the blade. Each hydraulic actuator is controlled through a valve which is connected to the single lever control. When the single lever control actuates to extend the push arms of the ram assemblies on each side of the C-frame the blade is pitched. When the single lever control is moved on a second axis one of the pusharms extends while the opposite pusharm retracts to produce a warping effect on the blade which tends to lower one side and raise the opposite side. Accordingly, when the single lever control is pivoted on this axis, the blade is pitched in one direction or the other depending on the direction of pivotal movement of a single lever control.

Accordingly, this arrangement provides a single lever control pivotal on two axes which permits the operator to pitch or tilt or provide a combination of pitching or tilting by the use of a single lever and permitting the operator to have the other hand available for other controls.

Accordingly, it is an object of this invention to provide a single lever control operating a valve means to selectively operate hydraulic actuators of a bulldozer blade singularly in either direction to extend the pusharms, or simultaneously extending and retracting the pusharms to selectively provide a pitch and tilt operation of the bulldozer'blade.

It is a further object of this invention to provide a single lever control valve means operating a hydraulic act-uator in each of two ram assemblies for simultaneous extension of said actuators to pitch the blade, or simultaneous extension and retraction of opposing actuators on opposite sides of the blade to selectively tiltthe blade.

The objects of this invention are accomplished by mounting a C-frame for pivotal movement about a horizontal axis on the chassis of the vehicle. The forward end of a C-frame is universally connected to the center point on the bulldozer blade. The ram assembly on each of the side beams of the C-frame provides a means for angling of the bulldozer blade through universal connections on the front end of the ram assemblies to each end of the bulldozer blade. The ram assembly includes a strut connected to the lower portion of the blade and a pusharm connected to the upper portion of the blade with each arm including a hydraulic actuator to rotate the blade on a transverse axis when both actuators are operated to extend the pusharms. The actuators also have means for simultaneously extending and retracting opposing hydraulic actuators to produce a pitching of the bulldozer blade on a longitudinal axis. The control for the hydraulic actuator is provided through a single lever control which is pivotal about two axes to permit actuation of a valve for each of the actuators which extends both actuators when the lever is pivoted on a first axis and extends and retracts opposing actuators when pivoting on a second axis. Accordingly, a single lever control and control valve will provide a control for pitching and tilting of a bulldozer blade as desired by the operator. v

The preferred embodiments of this invention are illustrated in the attached drawings.

FIG. 1 is a side view partially in section of a single lever control and the hydraulic control valve;

FIG. 2 is a front view of a single lever hydraulic control valve for operating the bulldozer blade;

FIG. 3 is a plan view illustrating a single lever control and the hydraulic valves;

FIG. 4 is a schematic illustration of the hydraulic system for operating the hydraulic actuators of the bulldozer blades;

FIG. 5 illustrates an isometric view of the single lever control on a tractor carrying a bulldozer blade; and

FIG. 6 is a cross section view of the return spring on the hydraulic control valve.

Referring to the drawings, the single lever l is welded to the T-block 15 which is supported for rotation about axis 10 on the stub shaft 3 journaled in bushings 2 of clevis 102. The clevis 102 is integral with the shank 4 which is received in the bushings 5 and 6 supported by the bearing bracket 7. The washer 8 is fastened on the end of a shank 4 by means of a nut 9 which holds the washer 8 in position against the radial flange 14 of the bushing 6. The radial flange 14 of the clevis 102 firmly seats against the radial flanges 13 of bushing 5. The flanges l3 and 14 operate as thrust bearings between the clevis 102 and the bracket 7 as well as the washer 8 and bracket 7. The single lever 1 is also free to rotate about the axis 12.

The clevis 102 supports the T-block 15 through the stub shaft 3 which is journaled in the T-block 15. The T-block 15 extends underneath the lever 1 to which it is welded. The lever 1 and the T-block 15 pivot on the stub shaft 3 which defines the pivotal axis 10. The pivoting of lever 1 about the transverse axis 10 operates both valve 17 and 18 simultaneously to extend or contract actuators 19 and 20. The lever l is held in a neutral position by centering springs in the valve assembly.

The lever 1 can be pivoted transversely about axis 12 as the shank 4 rotates within the bushings and 6. The T-block 15 is threaded on each end to receive a bolt 21 which has a shoulder 22 and a spherical head 23 which is received in a socket of link 24. The bolt 26 forms a hectagon shoulder 27 and a spherical head 28 which is received in a spherical socket of link 29. Link 24 is similarly connected to a bolt 30 which also has spherical head 31 and hexagon shoulder 32 and which is fastened to the bellcrank 33. The link 29 extends downwardly and is connected to a bolt 34 having a hectagon shoulder 35 and spherical head 36. The bolt 30 is fastened to the bellcrank 33 by the nut 37 while the bolt 34 is fastened to the bellcrank 38 by the nut 39. Bellcrank 33 is connected to the sleeve 40 while bellcrank 38 is fastened to the sleeve 140. The sleeve 40 carries a bushing 41 while sleeve 140 carries a bushing 42. The bushings 41 and 42 encircle the shaft 43 which is supported on brackets 44 and 45 which are connected to the tubular member 46. The tubular member 46 is supported by the chassis 47. The tubular member 46 also is connected to the end wall 48 and channel 49 which is fabricated with the formed plate 50 to provide a supporting structure for the valve assembly 51. The valve assembly 51 is provided with suitable conduits for connection to the hydraulic actuators l9 and 20 as well as the pump 52.

The valve assembly 51 comprises two valves 17 and 18. Each valve transmits fluid in one direction in response to movement of the bellcranks 33 and 38 in the first direction of the rotation and transmits fluid in the opposite direction in response to counterrotation of the bellcranks 33 and 38 in the opposite rotational direction. Each bellcrank is returned to a neutral position by a spring mechanism in the valves which in turn likewise returns the lever 1 to a neutral position. The valves 17 and 18 each include the return springs as shown in FIG. 6 which will be described subsequently.

The valve housing 53 supports a spring casing 54. The spool 55 moves reciprocally within the valve housing and threadedly receives the screw 56. The end of the spool 55 supports the spring seat 57 while the screw 56 supports the spring seat 58. The spring 59 is compressively positioned between the two spring seats. The spring seat 57 abuts the end of the housing 53 in the neutral position while the spring 58 abuts the inside end of the spring casing 54 when in the neutral position. When the valve is actuated and released with a space between the end of the spring casing 54 and the spring seat 58, spring 59 will cause a return movement of the spool in the right-hand direction while a clearance between the spring seat 57 and housing 53, spring 59 will cause a return movement of the spool 55 in the opposite direction to a neutral position. The force of this spring 59 returns the valve to a neutral position which likewise returns each of the bellcranks 44 and 45 to their centered position as well as the centered position of the lever 1 about the axes l0 and 12. FIG. 1 and 2 for the purpose of illustration shows the neutral position of the lever l on both axes described.

FIG. 4 illustrates the hydraulic system which includes a pump 52 receiving hydraulic fluid 65 from the reservoir 66. The conduit 67 connects a pump to the reservoir 66. The high pressure side of the pump 52 is connected to the conduit 68 which is in communication with the conduits 69 and 70 leading to valves 18 and 17 respectively. A return conduit 71 returns fluid from valve 18 while the return conduit 72 returns fluid from valve 17 to the reservoir 66.

Valves 18 and 17 are three position valves for transmitting fluid to the actuators 19 and 20. The actuators 19 and 20 provide a pivoting and tilting action for the bulldozer blade 74. The bulldozer blade 74 is connected to the ram assemblies 75 and 76. The ram assembly 75 includes a lower strut 77 and a pusharm 78 which includes actuator 20.

The'ram assembly 76includes a lower strut 79 and pusharm 80 which includes the hydraulic actuator 19. The ram assembly 75 includes a hydraulic actuator for angling as does the ram assembly 76 and a suitable control system for angling the blade about a vertical axis.

The bulldozer blade 74 can be lifted by suitable actuators in a hydraulic system through the hydraulic actuator 81 and 82. A control lever l is shown on the vehicle at the operators station for the control of the pitch and tilt of the bulldozer blade 74.

The operation of the device will be described in the following paragraphs.

Referring to FIG. 4 the pump 52 is driven by a suitable source of power arid draws fluid from the reservoir 66 through the conduit 67. The pump pressurizes fluid in conduits 68, 69 and 70 which is transmitted through the valves 17 and 18 to the hydraulic actuators 20 and 19 in response to actuation of the valves.

The blade 74 is controlled by the single lever 1. The supplying of pressurized fluid to the actuators 19 and 20 to simultaneously extend the actuators in the struts 80 and 78 will pitch the blade about a transverse axis by causing the top portion of the blade to roll forwardly relative to the lower portion of the blade. The blade can be pitched rearwardly by contracting both of the hydraulic actuators 19 and 20 which causes the blade to pivot also about the pivotal connection of the lower struts 79 and 77.

The blade 74 can be tilted by the contraction of one of the actuators with simultaneous extension of the other hydraulic actuators l9 and 20. This is accomplished by reversing the movement of the valve 17 while simultaneously moving the valve 18 forwardly or vice versa. While one actuator contracts the other actuator extends and produces a warping effect on the blade which in turn will cause the blade to lift on one side and be forced downwardly on the opposite side. The tilting action is produced by moving the single lever 1 sidewards to one side or the other depending on the direction of tilt required.

The single lever 1 is shown in FIGS. 1, 2 and 3 with its specific mounting on the vehicle. As the lever 1 is moved forwardly to rotate about axis 10 both of the bellcranks 33 and 38 rotate in a counterclockwise direction as shown in FIG. 1. With the counterclockwise rotation of the bellcranks the valves 17 and 18 are bothmoved forwardly permitting communication between the pump and the rearward side of the actuators l9 and through conduits 180 and 181 respectively. The fluid on the opposite side of the piston in the actuators returns through conduits 182 and 83 through the valves 18 and 17 to the reservoir 66. When the lever l is pivoted rearwardly as shown in FIG. 1 the bellcranks 33 and 38 also rotate in a clockwise direction causing the hydraulic actuators 19 and 20 to contract. When the lever l is rotated in a rearward direction or clockwise direction the bellcranks 33 and 38 are also rotated in a clockwise direction and the pressurized fluid flows through the valves 17 arid 18 to contract the hydraulic actuators 20 and 19.

The single lever control can be rotated about the longitudinal axis 12 which will produce a reversal of the direction of motion of the valves 17 and 18 relative to each other. When the single lever 1 is rotated in a clockwise direction as shown in FIG. 2 the bellcrank 33 will rotate in a counterclockwise direction as shown in FIG. 1 while the bellcrank 38 will rotate in a clockwise direction as shown in FIG. 1. This will cause pressurized fluid from the pump to flow through the valve 17 to extend the hydraulic actuator 20 while the pressurized fluid will flow through valve 18 to contract the hydraulic actuator 19. With an extension of hydraulic actuator 20 and contraction of hydraulic actuator 19 the blade will lift on the side of the actuator 19 and lower the blade on the side of the hydraulic actuator 20.

When the single lever control is moved in the counterclockwise direction as shown in FIG. 2 the reverse situation is accomplished and the hydraulic actuator 19 extends while the hydraulic actuator 20 contracts which in turn will cause the blade to tilt by raising the blade on the side of the hydraulic actuator 20 and lowering the side of actuator 19. Accordingly, the tilt and the pitch is controlled by the single lever and is dependent upon which axis of rotation the single lever l is rotated about.

It is understood that each of the valves 19 and 20 include a return spring 59 as shown in FIG. 6 when the valve spool is moved forwardly the spring 59 is compressed and the spring seat 58 moves away from the end of the spring casing 54. As soon as the lever is released the spring 59 forces the spring seat 58 up against the end wall of the spring casing 54. The reverse situation is true when the spool 55 is moved in a righthand direction. The spring seat 57 moves in the righthand direction away from the wall 85 of housing 53. When the lever is released the spring 59 moves the spring seat 57 against the cylinder wall and returns the valve to a neutral position and simultaneously returns the control lever 1 to its neutral position.

When the lever 1 is moved in a transverse direction androtates about the axis 12 the same springs return the lever to its neutral position. The only difference is that the spring seat 58 is moved away from the spring casing 54in the one actuator while the spring seat 57 is moved away from the wall 85 of housing 53 in the other valve. The spring 59 returns the spool to its normally neutral position when the lever is released. This again will return the lever to its neutral position when rotated in a transverse direction.

Accordingly, the preferred embodiment of this invention has been illustrated and described. The single lever controls pitch and tilt of the blade 74 in response to the direction of movement of the lever. The lever 1 always returns to a neutral position in response to spring actuators in the valve assemblies.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A hydraulic means for operating a bulldozer blade comprising, a vehicle, a bulldozer blade universally mounted on said vehicle for pivotal movement about a transverse axis to pitch said blade and for the pivotal movement generally about a longitudinal axis to tilt said blade, a pair of ram assemblies pivotally supported on said vehicle, each ram assembly including a strut and a pusharm universally connected to the lower and upper portion of said blade respectively, a hydraulic system including a source of pressurized fluid, a hydraulic actuator in each of said pusharms for extending or contracting said pusharms, a control valve connected between said source and each one of said actuators controlling the flow of pressurized fluid from said source to said hydraulic actuators, resilient means connected to each of said control valves normally biasing said valves to a centrally neutral position, a single control lever, means connecting said lever to both control valves to simultaneously control the flow of hydraulic fluid to each of said hydraulic actuators, pivotal support means supporting said lever forpivotal movement about two axes transverse to the length of the lever, said pivotal support means defining a first pivotal axis essentially parallel with said transverse axis whereby pivotal movement of said lever about said first axis provides simultaneous extension of said actuators to pitch said blade, said pivotal support means defining a second pivotal axis essentially parallel with said longitudinal axis whereby pivotal movement of said lever about said second axis differentially extend and contract said hydraulic actuators to tilt said blade and to thereby provide pivotal movement of said lever to simulate movement of said blade.

2. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said hydraulic actuators include double acting hydraulic actuators.

3. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said control valves include spring means biasing said valves and control lever to a neutral position.

4. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said lever defines transversely spaced arms, links connected to said arms, bellcranks connected to said links and said valves to operate said valves when said lever is operated.

5. A hydraulic means for operating a bulldozer blade as set forth in claim 1 including means defining said first pivotal axis for said control lever and means defining said second pivotal axis for said control lever, said control valves defining reciprocating axes parallel with said second axis, means connecting said lever with said valves to thereby reciprocally move said valves in the same direction when said lever is pivoted about said first axis. I

6. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said control valves include reciprocating spool valves.

7. A hydraulic means for operating a bulldozer blade as set forth in claim 1 including bracket means defining the second pivotal axis of rotation, 21 clevis means on said bracket means defining the first pivotal axis of rotation of said lever, said control valves including a bellcrank connected between each of said control valves and said control lever, spring means in each of said valves for returning each of said valves to a neutral position to thereby return said control lever to a normally neutral position.

8. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein a first control valve and a second control valves include a linkage connecting said control valve to said lever, said control lever selectively pivoting about the first and second axis of rotation to to differentially operate said control valves to tilt said blade.

10. A hydraulic means for operating a bulldozer blade as set forth in claim 1 including a frame pivotally supporting said strut and said pusharm.

UTED STATES PATENT OFFECE NMCATE OF QORECTEON Patent No. 39 7 ll- Dated October 214., 1972 Inventor(s) David A Berg It is certified that error appears in the above-identified patent :-'=1'ui. that said Letters Patent are hereby corrected as shown below:

Column 8, Claim 9, line )4, after "in" insert -,c1aim l--;

line Lt, cancel "1 including".

Signed and sealed this 8th day of January 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. I RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents FORM PO-105O (10-69) v i -gc 5037a-p59 I U45. GOVERNMENT PRiuTING OFFICE: 959 0-16533L 

1. A hydraulic means for operating a bulldozer blade comprising, a vehicle, a bulldozer blade universally mounted on said vehicle for pivotal movement about a transverse axis to pitch said blade and for the pivotal movement generally about a longitudinal axis to tilt said blade, a pair of ram assemblies pivotally supported on said vehicle, each ram assembly including a strut and a pusharm universally connected to the lower and upper portion of said blade respectively, a hydraulic system including a source of pressurized fluid, a hydraulic actuator in each of said pusharms for extending or contracting said pusharms, a control valve connected between said source and each one of said actuators controlling the flow of pressurized fluid from said source to said hydraulic actuators, resilient means connected to each of said control valves normally biasing said valves to a centrally neutral position, a single control lever, means connecting said lever to both control valves to simultaneously control the flow of hydraulic fluid to each of said hydraulic actuators, pivotal support means supporting said lever for pivotal movement about two axes transverse to the length of the lever, said pivotal support means defining a first pivotal axis essentially parallel with said transverse axis whereby pivotal movement of said lever about said first axis provides simultaneous extension of said actuators to pitch said blade, said pivotal support means defining a second pivotal axis essentially parallel with said longitudinal axis whereby pivotal movement of said lever about said second axis differentially extend and contract said hydraulic actuators to tilt said blade and to thereby provide pivotal movement of said lever to simulate movement of said blade.
 2. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said hydraulic actuators include double acting hydraulic actuators.
 3. A hydraulic means for operating a bulldozer blade as set forth in claim 1 whErein said control valves include spring means biasing said valves and control lever to a neutral position.
 4. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said lever defines transversely spaced arms, links connected to said arms, bellcranks connected to said links and said valves to operate said valves when said lever is operated.
 5. A hydraulic means for operating a bulldozer blade as set forth in claim 1 including means defining said first pivotal axis for said control lever and means defining said second pivotal axis for said control lever, said control valves defining reciprocating axes parallel with said second axis, means connecting said lever with said valves to thereby reciprocally move said valves in the same direction when said lever is pivoted about said first axis.
 6. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein said control valves include reciprocating spool valves.
 7. A hydraulic means for operating a bulldozer blade as set forth in claim 1 including bracket means defining the second pivotal axis of rotation, a clevis means on said bracket means defining the first pivotal axis of rotation of said lever, said control valves including a bellcrank connected between each of said control valves and said control lever, spring means in each of said valves for returning each of said valves to a neutral position to thereby return said control lever to a normally neutral position.
 8. A hydraulic means for operating a bulldozer blade as set forth in claim 1 wherein a first control valve and a second control valves include a linkage connecting said control valve to said lever, said control lever selectively pivoting about the first and second axis of rotation to simultaneously actuate said valves for pitching and tilting said bulldozer blade.
 9. A hydraulic means for operating a bulldozer blade as set forth in including, 1 including a bearing bracket supported on said vehicle, a clevis including a shank pivotally mounted in said bearing bracket defining the second axis, means on said lever journaled in said clevis defining the first axis at movement for said control lever, said control lever thereby rotating about the first axis to simultaneously operate said control valves to pitch said blade and about said second axis of rotation to differentially operate said control valves to tilt said blade.
 10. A hydraulic means for operating a bulldozer blade as set forth in claim 1 including a frame pivotally supporting said strut and said pusharm. 